Refine
Document Type
- Doctoral thesis (1)
Has Fulltext
- yes (1)
Is part of the Bibliography
- no (1)
Year of publication
- 2009 (1)
Language
- English (1)
Keywords
- Oberflächenanalyse (1)
- Optics (1)
- Optik (1)
- Selbstorganisierte elektrochemische Systeme (1)
- Self-organized electrochemical systems (1)
- Silicium (1)
- Siliciumdioxid (1)
- Silicon (1)
- Surface analysis (1)
Institute
Nanotopography development induced by photoelectrochemical in situ conditioning of silicon is followed using a combination of surface sensitive analysis techniques. In an etching study, vertical nanostructure analysis reveals a buried stressed layer within silicon, identified by Brewster-angle analysis (BAA). In conjunction with in system synchrotron radiation photoelectron spectroscopy (SRPES), a superior quality hydrogen terminated Si(111) surface could be prepared by obliteration of the intermediate stressed layer. Using a novel photoelectrochemical structure formation method, a variety of vertical nanotopographies has been generated and analyzed by in situ Brewster-angle reflectometry (BAR) and scanning probe microscopy (SPM). Shaping of the nanostructures became possible by real-time monitoring using BAR. Appearances range from aligned single nanoislands with improved aspect ratio to connected Si nano-networks. A model was developed to describe the nanostructure formation based on stress-induced selective oxidation. Increased local photo-oxidation is found to result in the formation of extended horizontal micro- and nanostructures with fractal properties. Within a defined light intensity range, the structures reveal the azimuthal symmetry of the investigated crystal planes (111), (100), (110) and (113). The observed features could be reproduced using a model that is based on the interplay of stress in silicon, oxidation by light generated excess holes and locally increased etching in fluoride containing solution.